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Contraction Joints The purpose of contraction joints is to control cracking caused by temperature changes
Figure 7-20-Location of construction joints in beams, columns, and floor slabs.
Figure 7-22.-Use of a contraction Joint. incident to shrinkage of the concrete. A typical dummy contraction joint (fig. 7-22) is usually formed by cutting a depth of one third to one fourth the thickness of the section. Some contracting joints are made with no filler or with a thin coat of paraffii or asphalt and/or other materials to break the bond. Depending on the extent of local temperature, joints in reinforced concrete slabs may be placed at 15-to 25-ft intervals in each direction. |
 
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